JP2017184543A - Power source controller for vehicle and control method of power supply device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently discharge an electric charge accumulated in a capacitor.SOLUTION: A poser source controller executes: a first discharge control that discharges an accumulated electric charge to a capacitor 4 comprised to a vehicle 2 to a battery 5 for driving an auxiliary machine 6 mounted on the vehicle 2; and a second discharge control that discharges the electric charge of the capacitor 4 to a ground GND when a charging amount of the battery 5 is reached to a predetermined threshold value during the first discharge control. Thus, the electric charge of the capacitor 4 can be discharged even after the charge of the battery 5 is filled. Therefore, deterioration of the capacitor 4 can be prevented without remaining the electric charge in the capacitor 4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for discharging electric charges accumulated in a capacitor provided in a vehicle.

  Conventionally, in addition to a secondary battery such as a lead battery, a capacitor or the like that assists the secondary battery is mounted on the vehicle. When such a vehicle is stopped, a technique is known in which charges accumulated in a capacitor are discharged to a lead battery to prevent deterioration. For example, the technique of Patent Document 1 discloses a technique for discharging capacitor charges to a charger and preventing capacitor deterioration.

JP2013-225996A

  However, when the lead battery is fully charged, the capacitor cannot be discharged any more, and charge may remain in the capacitor. In this case, the capacitor may be deteriorated due to the influence of the remaining charge.

  In view of the above problems, an object of the present invention is to provide a technique for sufficiently discharging charges accumulated in a capacitor.

  In order to solve the above-mentioned problems, a first aspect of the present invention is a power supply control device for a vehicle used in a vehicle, wherein electric charges stored in a capacitor provided in the vehicle are driven to drive a device mounted on the vehicle. Discharge means for executing first discharge control for discharging to a secondary battery that performs discharge and second discharge control for discharging to ground, and determination means for determining whether the charge amount of the secondary battery has reached a predetermined threshold value; The discharging means executes the second discharge control when the amount of charge of the secondary battery reaches the predetermined threshold during the execution of the first discharge control.

  According to a second aspect of the present invention, in the vehicular power supply control device according to the first aspect, the discharge means executes the second discharge control while performing a current restriction that restricts a current that is supplied to the capacitor. .

  According to a third aspect of the present invention, in the vehicular power supply control device according to the second aspect, the discharge means performs the current limitation by performing step-down control for stepping down a voltage applied by the capacitor.

  According to a fourth aspect of the present invention, in the vehicle power supply control device according to the third aspect, the first switch element that opens and closes a circuit connecting the capacitor and the ground, the first switch element of the circuit, and the And an inductor connected to the ground, wherein the discharging means performs the step-down control by switching the first switch element.

  According to a fifth aspect of the present invention, in the vehicular power supply control device according to any one of the first to fourth aspects, the discharging means includes the capacitor, the first switch element, and the second switch element on a primary side. An H-bridge circuit in which the secondary battery, the third switch element, and the fourth switch element are connected to the secondary side, and the inductor is connected between the primary side and the secondary side.

  The invention of claim 6 further comprises ignition detection means for detecting that an ignition switch provided in the vehicle is turned off in the vehicle power supply control device according to any one of claims 1 to 5, The discharging means discharges the electric charge accumulated in the capacitor when the ignition switch is turned off.

  The invention according to claim 7 is the vehicle power supply control device according to any one of claims 1 to 5, further comprising abnormality detection means for detecting an abnormality of the vehicle power supply control device, wherein the discharge means comprises: When the abnormality is detected, the charge accumulated in the capacitor is discharged.

  The invention according to claim 8 is the vehicular power supply control device according to any one of claims 1 to 5, further comprising replacement detection means for detecting replacement of the capacitor, wherein the discharging means includes the capacitor. When the battery is replaced, the charge accumulated in the capacitor is discharged.

  The invention according to claim 9 is a method for controlling a vehicle power source used in a vehicle, and (a) drives a device mounted on the vehicle with charges accumulated in a capacitor provided in the vehicle. A step of discharging to the secondary battery; (b) a step of determining whether a charge amount of the secondary battery has reached a predetermined threshold; and (c) the secondary battery during the step (a). And a step of discharging the charge accumulated in the capacitor to the ground when the amount of charge reaches the predetermined threshold value.

  According to the first to ninth aspects of the present invention, when the charge amount of the secondary battery reaches a predetermined threshold value, the charge accumulated in the capacitor is discharged to the ground, so that the capacitor can be sufficiently discharged.

  In particular, according to the second aspect of the present invention, since the current flowing through the capacitor is limited, stable discharge can be achieved.

  In particular, according to the third aspect of the invention, since the step-down control for stepping down the voltage applied by the capacitor is performed, the current flowing through the capacitor can be stably limited.

  In particular, according to the invention of claim 4, since the step-down control is performed by switching the first switch element and the capacitor energizing the inductor, it is possible to discharge while suppressing the generation of a large current.

  In particular, according to the invention of claim 5, since the H-bridge circuit is used, discharge can be performed with a simple configuration.

  In particular, according to the invention of claim 6, since the discharge is performed when the ignition switch is turned off, it is possible to prevent the capacitor from deteriorating by suppressing the charge remaining in the capacitor.

  In particular, according to the seventh aspect of the invention, since discharge is performed when an abnormality is detected in the vehicle power supply control device, safety can be improved.

  In particular, according to the invention of claim 8, since the capacitor is discharged when it is replaced, the capacitor can be replaced more safely.

FIG. 1 shows an outline of a power supply system according to the first embodiment. FIG. 2 shows the configuration of the power supply system according to the first embodiment. FIG. 3 shows the configuration of the H-bridge circuit according to the first embodiment. FIG. 4 shows the configuration of the DCDC control driver according to the first embodiment. FIG. 5 shows the discharge path to the battery in the H-bridge circuit. FIG. 6 shows a discharge path to the ground in the H-bridge circuit. FIG. 7 shows a path for stopping discharge in the H-bridge circuit. FIG. 8 shows a timing chart of the discharge control. FIG. 9 is a flowchart showing the processing steps of the DCDC control driver according to the first embodiment. FIG. 10 is a flowchart showing processing steps of the DCDC control driver according to the first embodiment. FIG. 11 is a flowchart showing the processing steps of the DCDC control driver according to the first embodiment. FIG. 12 shows the configuration of a DCDC control driver according to the second embodiment. FIG. 13 is a flowchart illustrating processing steps of the DCDC control driver according to the second embodiment. FIG. 14 shows the configuration of a DCDC control driver according to the third embodiment. FIG. 15 is a flowchart showing the processing steps of the DCDC control driver according to the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
<1-1. Overview>
FIG. 1 shows an overview of a power supply control system 1 according to the first embodiment. The power supply control system 1 is a control system that controls the DCDC converter 3, the capacitor 4, the battery 5, the auxiliary machine 6, the starter 7, and the alternator 8 that are connected to each other in the vehicle 2.

  The power supply control system 1 appropriately distributes the power from the alternator 8 serving as a generator to the capacitor 4 and the battery 5. Thereby, the charging state of the capacitor 4 and the battery 5 is not lowered more than necessary, and the auxiliary device 6 (navigation device, headlight, etc.) can be stably operated, and the capacitor 4 and the battery 5 can be efficiently discharged.

  The battery 5 and the capacitor 4 are connected via a DCDC converter 3 which is a bidirectional step-up / step-down device, and charging from the battery 5 to the capacitor 4 or charging from the capacitor 4 to the battery 5 or the auxiliary machine 6 according to the traveling mode of the vehicle 2. Perform discharge control. The DCDC converter 3 can perform step-up / step-down control that can output current bidirectionally, and includes an H-bridge type circuit.

  For example, the regenerative power generation energy of the alternator 8 is charged into the capacitor 4 during deceleration after steady running, and the electric power stored in the capacitor 4 is supplied to the auxiliary device 6 on the battery 5 side through the DCDC converter 3 during subsequent running or stopping. To do. Thereby, the battery power consumption during driving | running | working is suppressed and the alternator 8 electric power generation opportunity is reduced. In addition, fuel injection due to power generation load is suppressed to improve fuel efficiency and reduce engine load.

  On the other hand, when the vehicle is not traveling (the vehicle is stopped when the user is not driving), the power supply control system 1 is stopped, and the capacitor 4 is not charged / discharged and the voltage is maintained. When the voltage of the capacitor 4 is maintained at, for example, 15 [v] for a long time, the deterioration of the capacitor is promoted, and the characteristics are deteriorated due to the decrease in the capacity and the increase of the internal ESR.

  In order to solve such a problem, discharge control from the capacitor 4 to the battery 5 is performed when the vehicle is stopped (when the ignition switch is turned off), and the voltage of the capacitor 4 is sufficiently reduced to, for example, about 5 [v] before the power source. It is preferable to stop (end processing) the control system.

  However, during the discharge control after the ignition switch is turned off, the operation of the auxiliary machine 6 is stopped, so that the power consumption of the auxiliary machine 6 is small and most of the discharged power from the capacitor 4 is charged in the battery 5. For this reason, when the battery 5 is fully charged during the discharge control of the capacitor 4, the discharge control is stopped in order to prevent the battery 5 from being overcharged. In this case, the capacitor 4 cannot be sufficiently discharged, and the voltage of the capacitor 4 is maintained in a high state to shut down the power supply control system 1. If the voltage of the capacitor 4 is maintained in a high state, the problem that the deterioration of the capacitor 4 is promoted remains as described above. The present invention for solving such problems will be described in detail below.

<1-2. Configuration>
FIG. 2 shows the configuration of the power supply control system 1. The power supply control system 1 is mounted on a vehicle 2 and includes a DCDC converter 3 (hereinafter abbreviated as “DDC”), a capacitor 4, a battery 5, an auxiliary machine 6, a starter 7, an alternator 8, and a main relay 9. The DDC 3, the capacitor 4, the battery 5, the auxiliary machine 6, the starter 7, and the alternator 8 are connected to each other. The DDC 3, the battery 5, and the main relay 9 are connected to each other. An ignition switch IGSW is connected between the DDC 3 and the main relay 9 and the battery 5.

  The battery 5 is a secondary battery using lead as an electrode. The battery 5 is a main power source for auxiliary equipment provided in the vehicle 2.

  The DDC 3 is a DC converter that converts a DC voltage (current) into another DC voltage (current). Further, it is a transformer that steps down or boosts a DC voltage. The DDC 3 adjusts the power between the capacitor 4 and the battery 5 according to the driving state of the vehicle 2. The DDC 3 includes an H bridge circuit 31 and a DCDC control driver (hereinafter abbreviated as “DDC driver”) 32. The DDC 3 functions as a vehicle power supply control device.

  The H bridge circuit 31 includes a switch and a coil, and is a circuit that energizes the capacitor 4 (described later) from the capacitor 4 to the battery 5 or the ground while limiting the current to a constant value. The H bridge circuit 31 functions as a discharging unit.

  The DDC driver 32 transmits a Drive signal to the switch provided in the H bridge circuit 31 to switch the switch on or off. The configurations of the H bridge circuit 31 and the DDC driver 32 will be described later.

  The capacitor 4 is a storage battery (capacitor) that stores electric charges. For example, an electric double layer capacitor (EDLC). The EDLC has excellent cycle characteristics, has a long life, and is suitable for application to the power supply control system 1. The capacitor 4 serves as an auxiliary power source for driving an auxiliary machine 6 described later according to the driving state of the vehicle 2 or charging the battery 5 whose voltage has dropped.

  If electric charge remains in the capacitor 4, the polarizable pores are blocked, causing a decrease in capacitance and an increase in internal resistance. That is, the capacitor 4 is deteriorated. Therefore, it is preferable to discharge the charge accumulated in the capacitor 4 after the vehicle 2 is stopped.

  The auxiliary machine 6 is an electric device mounted on the vehicle 2. For example, navigation devices, audio, air conditioners, lights, power steering, power windows, etc. The auxiliary machine 6 is driven by being supplied with power from the capacitor 4 and the battery 5.

  The starter 7 is a starting device that includes an electric motor and starts the engine of the vehicle 2.

  The alternator 8 is a device that generates electric power using the rotation of the engine of the vehicle 2 as a power source. In addition, when the vehicle 2 is decelerated, regenerative electric power is generated by regenerative braking.

  The main relay 9 is a device that supplies / cuts off power to the DDC 3 in accordance with the on / off of the ignition switch IGSW. When the ignition switch IGSW is turned on and an IGin signal is transmitted to the DDC 3 and the main relay 9, the main relay 9 transmits an Enable signal to the DDC 3 to supply power. In addition, when the ignition switch IGSW is turned off and the transmission of the IGin signal is stopped, the DDC 3 transmits a Hold signal to the main relay 9 and continuously obtains power. During this time, the DDC 3 performs discharge control of the capacitor.

  Next, the configuration of the H bridge circuit 31 provided in the DDC 3 will be described. FIG. 3 shows a configuration of the H bridge circuit 31.

  In the H bridge circuit 31, the capacitor 4 and the first switch M1 are connected to the high side on the primary side, and the second switch M2 is connected to the low side.

  In the H bridge circuit 31, the battery 5 and the third switch M3 are connected to the secondary high side, and the fourth switch M4 is connected to the low side.

  A coil L is connected between the first switch M1 and the second switch M2, and the third switch M3 and the fourth switch M4. The second switch M2 and the fourth switch M4 are connected (grounded) to the ground.

  The first switch M1 to the fourth switch M4 are switch elements that control a short circuit and an open circuit. For example, it is a bipolar transistor or FET (field-effect transistor). In particular, a MOS-FET (metal-oxide-semiconductor field-effect transistor) is preferable. That is, the MOS-FET does not require a bias current unlike a bipolar transistor and has low power. This is because a bipolar transistor forms two PN junctions of PNP or NPN in the vertical direction, whereas a MOS-FET is suitable for high integration because an insulating layer and a gate electrode need only be provided on both electrodes. . Each of the first switch M <b> 1 to the fourth switch M <b> 4 is connected to the DDC driver 32. Accordingly, the first switch M1 to the fourth switch M4 are controlled to be turned on or off by the DDC driver 32.

  The coil L is a passive element that accumulates energy in a magnetic field formed by an energized current. It is a so-called inductor.

  Next, the configuration of the DDC driver 32 will be described. FIG. 4 shows the configuration of the DDC driver 32.

  The DDC driver 32 includes a control unit 321 and a storage unit 322.

  The control unit 321 is a microcomputer including a CPU, a RAM, and a ROM. The control unit 321 controls the entire DDC driver 32. The control unit 321 includes an IG detection unit 321a, a power supply holding unit 321b, a charge determination unit 321c, and a discharge control unit 321d.

  The IG detection unit 321a detects the stop of the transmission of the IGin signal and detects that the ignition switch IGSW is turned off. The IG detector 321a functions as an ignition detector.

  The power supply holding unit 321b holds a power supply for driving the DDC 3 while discharging the capacitor 4 after the ignition switch IGSW is turned off. The power holding unit 321b transmits a Hold signal indicating that the power should be held to the main relay 9 so that the main relay 9 does not cut off the power to the DDC 3.

  The charge determination unit 321 c determines the amount of charge charged in the battery 5. The charge determination unit 321c determines the amount of charge of the battery 5 based on whether or not the voltage of the battery 5 has reached a predetermined threshold value. The threshold value is indicated by a charging threshold value Vtb described later.

  The discharge controller 321d controls the first switch M1 to the fourth switch M4 of the H bridge circuit 31, and discharges the charge of the capacitor 4 to the battery 5 or the ground GND. The discharge controller 321d controls the first switch M1 to the fourth switch M4 so that the charge of the capacitor 4 is discharged to the battery 5 when the ignition switch IGSW is turned off. In addition, after discharging the charge of the capacitor 4 to the battery 5, the discharge control unit 321d performs the fourth switch from the first switch M1 to discharge the charge of the capacitor 4 to the ground GND when the voltage of the battery 5 reaches a predetermined threshold. The switch M4 is controlled. Further, the discharge control unit 321d discharges the charge of the capacitor 4 to the ground GND until the voltage of the capacitor 4 reaches a predetermined threshold, that is, until the charge is sufficiently discharged.

  Thereby, even if the charge amount of the battery 5 is high and the charge of the capacitor 4 cannot be discharged to the battery 5, the charge of the capacitor 4 is discharged to the ground GND, so that the charge of the capacitor 4 does not remain. By preventing the charge of the capacitor 4 from remaining, the deterioration of the capacitor 4 can be prevented.

  The storage unit 322 is a storage medium that stores data. For example, it is a nonvolatile memory such as an EEPROM (Electrical Erasable Programmable Read-Only Memory) or a flash memory. The storage unit 322 stores a charging threshold value Vtb, a discharging threshold value Vtc, and a program P.

  The charging threshold Vtb is a voltage value indicating that the battery 5 is fully charged. For example, 14 [v]. The charge threshold value Vtb is read to the charge determination unit 321c and compared with the voltage of the battery 5.

  The discharge threshold Vtc is a voltage value indicating that the capacitor 4 has been sufficiently discharged. For example, 3 [v]. The discharge threshold value Vtc is read to the discharge control unit 321d and compared with the voltage of the capacitor 4.

  The program P is firmware that is read by the control unit 321 and executed for the control unit 321 to control the DDC 3.

<1-3. Operation>
Next, the operation of the H bridge circuit 31 will be described. 5 to 7 show a switching state in which the electric charge of the capacitor 4 energizes the H bridge circuit 31 and is discharged to the battery 5 or the ground GND.

  FIG. 5 shows a first switching state in which the electric charge of the capacitor 4 is discharged to the battery 5. The first switching state is a switching state in which the DDC driver 32 is formed with the first switch M1 and the second switch M2 turned on and the third switch M3 and the fourth switch M4 turned off.

  When the first switching state is formed, the electric charge of the capacitor 4 is energized to the battery 5 through the first switch M1, the coil L, and the third switch M3.

  FIG. 6 shows a second switching state in which the charge of the capacitor 4 is discharged to the ground GND. The second switching state is a switching state in which the DDC driver 32 is formed by turning on the first switch M1 and the fourth switch M4 and turning off the second switch M2 and the third switch M3.

  When the second switching state is formed, the electric charge of the capacitor 4 is energized to the ground GND through the first switch M1, the coil L, and the fourth switch M4.

  In addition, by switching between the first switching state and the second switching state, that is, by switching the third switch M3 on and off, the boost control to the capacitor 4 is performed.

  FIG. 7 shows a third switching state in which current flows back on the low side of the H-bridge circuit 31. The third switching state is a circuit formed by the DDC driver 32 turning on the fourth switch M4 and turning off the first switch M1, the second switch M2, and the third switch M3.

  When the third switching state is formed, the charge of the capacitor 4 is not energized, and the body diode (parasitic diode) of the second switch M2 generates the current IR, and the generated current IR is applied to the coil L and the fourth. The power is passed through the switch M4 to the ground GND.

  Note that the step-down control from the capacitor 4 to the ground GND is performed by switching between the second switching state and the third switching state, that is, by switching the fourth switch M4 on and off.

  Next, the switching state of the first switch M1 to the fourth switch M4 of the H bridge circuit 31 and the transition of the voltage of the capacitor 4 and the battery 5 will be described. FIG. 8 is a timing chart showing the switching state of the first switch M1 to the fourth switch M4, the transition of the voltage of the capacitor 4 and the battery 5, and the like.

  First, at time t1, the ignition switch IGSW is turned off. At this time, the capacitor voltage VCAP is 10 [v], and the battery voltage VBAT is 12 [v].

  Next, at time t2, a second switching state is formed. That is, the first switch M1 is turned on, the second switch M2 is turned off, the third switch M3 is turned off, and the fourth switch M4 is turned on.

  By forming the second switching state, a capacitor current ICAP that is a current value flowing out of the capacitor is energized to the ground GND. As a result, a coil current IL and a capacitor current ICAP that are current values flowing through the coil are generated, and both current values are increased. Since capacitor current ICAP is energized to ground GND, battery current IBAT flowing into the battery is not generated. At this time, the capacitor voltage VCAP, which is the voltage value of the capacitor, starts to decrease. That is, the charge accumulated in the capacitor 4 is discharged.

  At time t3, the first switching state is formed. That is, the first switch M1 is turned on, the second switch M2 is turned off, the third switch M3 is turned on, and the fourth switch M4 is turned off.

  The capacitor current ICAP is energized to the battery 5 by forming the first switching state. Therefore, after the current value of the battery current IBAT increases, it gradually decreases due to the action of the coil. Further, the coil current IL and the capacitor current ICAP also gradually decrease due to the action of the coil. At this time, the capacitor voltage VCAP further decreases and the battery voltage VBAT starts increasing.

  After time t4, the second switching state and the third switching state are alternately repeated until the battery voltage VBAT reaches the charging threshold value Vtb. As a result, the coil current IL and the capacitor current ICAP are gradually increased and decreased to maintain a constant current value, thereby preventing the generation of a large current and preventing the battery 5 and the H bridge circuit 31 from being damaged.

  As described above, since the capacitor voltage VCAP is about 10 [v] and the battery voltage VBAT is about 12 [v] at the start of discharging of the capacitor 4, the capacitor voltage VCAP is lower than the battery voltage VBAT. Therefore, the capacitor current ICAP can be smoothly supplied to the battery 5 by performing step-up control that alternately repeats the second switching state and the first switching state.

  When the battery voltage VBAT reaches the charging threshold value Vtb at time t14, the third switching state is formed, and the discharging control method is switched. That is, all of the first switch M1 to the fourth switch M4 are turned off. After time t14, since the battery 5 is fully charged, the capacitor current ICAP is not supplied to the battery 5 but is supplied to the ground GND. Thereby, the charge of the capacitor 4 can be discharged even after the battery 5 is fully charged.

  At time t15, the second switching state is formed again, and the capacitor current ICAP is energized to the ground GND.

  After time t16, the third switching state and the second switching state are alternately repeated until the capacitor voltage VCAP reaches 3 [v] which is the discharge threshold value Vtc. Further, step-down control from the capacitor 4 to the ground GND can be performed by alternately repeating the third switching state and the second switching state. Therefore, the capacitor 4 is discharged while performing step-down control of the capacitor 4. That is, since the voltage of the ground GND is 0 [v], the capacitor 4 is stepped down to approach the voltage value of the ground GND to prevent the generation of a large current.

  When the capacitor voltage VCAP reaches the discharge threshold value Vtc at time t30, it can be determined that the capacitor 4 has been sufficiently discharged, and thus the discharge control is stopped. Then, the power control system is shut down.

  Thus, from time t1 to time t14 when the battery voltage VBAT reaches the charging threshold value Vtb is the first discharge control for discharging the charge of the capacitor 4 to the battery 5. Further, from time t14 to time t30 when the capacitor voltage VCAP reaches the discharge threshold value Vtc is the second discharge control for discharging the charge of the capacitor 4 to the ground GND.

  In addition, by always energizing the coil L of the H-bridge circuit 31 with the capacitor current ICAP, duty control can be performed by switching from the first switch M1 to the fourth switch M4 to limit the capacitor current ICAP. For this reason, generation | occurrence | production of a large current and the power consumption of an electronic component can be prevented from becoming excessive.

<1-4. Processing>
Next, processing steps of the DDC driver 32 will be described. FIG. 9 is a flowchart showing processing steps of the DDC driver 32. The process shown in FIG. 9 is repeatedly executed at a predetermined cycle.

  First, the IG detection unit 321a determines whether or not the ignition switch IGSW is turned off (step S11). As described above, the IG detection unit 321a makes such a determination based on whether or not the IGin signal is stopped.

  When the IG detection unit 321a determines that the ignition switch IGSW is not turned off (No in step S11), the process ends. This is because discharge control is not necessary.

  On the other hand, when the IG detection unit 321a determines that the ignition switch IGSW is turned off (Yes in step S11), the discharge control unit 321d determines whether the capacitor voltage VCAP is greater than the discharge threshold Vtc (step S12). At this time, the power supply holding unit 321b transmits a Hold signal to the main relay 9 so that the power supply is continued even after the ignition switch IGSW is turned off.

  If the discharge controller 321d determines that the capacitor voltage VCAP is greater than the discharge threshold Vtc (Yes in step S12), the charge determiner 321c determines whether or not the battery voltage VBAT is less than the charge threshold Vtb (step S13).

  When the charge determination unit 321c determines that the battery voltage VBAT is smaller than the charge threshold value Vtb (Yes in step S13), the discharge control unit 321d executes the first discharge control (step S14). In this case, electric charge remains in the capacitor 4, and the battery 5 is in a state where there is room for charging. As described above, the first discharge control is a control state from time t1 to time t14 in which the second switching state and the first switching state are alternately repeated.

  On the other hand, when the charge determination unit 321c determines that the battery voltage VBAT is not smaller than the charge threshold value Vtb (No in step S13), the discharge control unit 321d executes the second discharge control (step S15). In this case, the electric charge remains in the capacitor 4, but the battery 5 has no room for charging. As described above, the second discharge control is a control state from time t14 to time t30 in which the third switching state and the second switching state are alternately repeated.

  When the discharge control unit 321d executes the first discharge control or the second discharge control, the process returns to step S12, and the discharge control unit 321d determines again whether or not the capacitor voltage VCAP is larger than the discharge threshold value Vtc (step S12). .

  If the discharge control unit 321d determines that the capacitor voltage VCAP is not greater than the discharge threshold Vtc (No in step S12), that is, determines that the charge of the capacitor 4 has been sufficiently discharged, the discharge control unit 321d stops the discharge control (step S16). The discharge controller 321d stops the discharge control by turning off the first switch M1 to the fourth switch M4. When the discharge control unit 321d stops the discharge control, the process ends.

  Next, details of the first discharge control in step S14 will be described. FIG. 10 is a flowchart showing detailed processing steps of the first discharge control.

  When step S14 starts, the discharge controller 321d turns on the first switch M1 (step S14a), turns off the second switch M2 and the third switch M3 (steps S14b and S14c), and turns on the fourth switch M4. (Step S14d). Next, the discharge control unit 321d waits until a predetermined time elapses while maintaining the switch state from the first switch M1 to the fourth switch M4, that is, the second switching state (step S14e).

  When the discharge control unit 321d determines that the predetermined time has elapsed (Yes in Step S14e), the first switch M1 is turned on (Step S14f), the second switch M2 is turned off (Step S14g), and the third switch M3 is turned on ( In step S14h), the fourth switch M4 is turned off (step S14i). Next, the discharge control unit 321d waits until a predetermined time elapses while maintaining the switch state from the first switch M1 to the fourth switch M4, that is, the first switching state (step S14j). When the discharge control unit 321d determines that the predetermined time has elapsed (Yes in step S14j), the process returns to the process of FIG.

  As described above, the discharge controller 321d repeatedly forms the second switching state and the first switching state, so that the charge of the capacitor 4 can be discharged to the battery 5 while performing the boost control.

  Next, the details of the second discharge control in step S15 will be described. FIG. 11 is a flowchart showing detailed processing steps of the second discharge control.

  When step S15 starts, the discharge control unit 321d turns on the first switch M1 (step S15a), turns off the second switch M2 and the third switch M3 (steps S15b and S15c), and turns on the fourth switch M4. (Step S15d). Next, the discharge control unit 321d waits until a predetermined time elapses while maintaining the switch state from the first switch M1 to the fourth switch M4, that is, the third switching state (step S15e).

  When the discharge control unit 321d determines that the predetermined time has elapsed (Yes in Step S15e), the first switch M1 is turned on (Step S15f), the second switch M2 is turned off (Step S15g), and the third switch M3 is turned off ( In step S15h), the fourth switch M4 is turned on (step S15i). Next, the discharge control unit 321d waits until a predetermined time elapses while maintaining the switch state from the first switch M1 to the fourth switch M4, that is, the second switching state (step S15j). When the discharge control unit 321d determines that the predetermined time has elapsed (Yes in step S15j), the process returns to the process of FIG.

  As described above, the discharge control unit 321d repeatedly forms the third switching state and the second switching state, so that the charge of the capacitor 4 can be discharged to the ground GND while performing step-down control.

  As described above, the DDC 3 according to the first embodiment discharges the electric charge accumulated in the capacitor 4 provided in the vehicle 2 to the battery 5 that drives the auxiliary device 6 mounted in the vehicle 2. The control and the second discharge control for discharging the charge of the capacitor 4 to the ground GND when the charge amount of the battery 5 reaches a predetermined threshold value during the first discharge control are executed. Thereby, the electric charge of the capacitor 4 can be discharged even after the battery 5 is fully charged. Therefore, no charge remains in the capacitor 4 and deterioration of the capacitor 4 can be prevented.

  The capacitor 4 can be discharged by forming a path for short-circuiting the capacitor 4 and the ground GND by a switch element or the like without using the H bridge circuit 31 as in the present embodiment. However, since the power supply control system 1 that controls two power supplies includes the large-capacity capacitor 4 as a sub power supply, the discharge peak current cannot be limited and becomes extremely large. In this case, there is a risk of causing burning destruction of the electronic components provided in the system. Therefore, in the present embodiment, as described above, it is not necessary to provide a separate discharge path, and by restricting, that is, controlling the discharge current, generation of a large current can be avoided and burnout destruction of the electronic component can be prevented.

<2. Second Embodiment>
Next, a second embodiment will be described. The second embodiment includes a configuration similar to that of the first embodiment. Therefore, differences from the first embodiment will be mainly described below.

<2-1. Overview>
In the first embodiment, the charge discharge control of the capacitor 4 is performed when the ignition switch IGSW is turned off. In the second embodiment, discharge control is performed when an abnormality occurs in the power supply control system. In particular, discharge control is performed when an abnormality occurs in a microcomputer mounted on an electronic control unit that controls the auxiliary machine 6. Thereby, before the power supply control system is stopped in response to the occurrence of the abnormality, that is, before the charge / discharge control of the capacitor 4 is stopped, the charge of the capacitor 4 can be reliably discharged. Therefore, even if the charge / discharge control of the capacitor 4 is stopped, the deterioration of the capacitor 4 can be prevented.

<2-2. Configuration>
FIG. 12 shows a configuration of the DDC driver 32 included in the DDC 3 according to the second embodiment. In the DDC driver 32 according to the first embodiment described above, the control unit 321 includes the IG detection unit 321a. In contrast, the DDC driver 32 according to the second embodiment includes the abnormality detection unit 321e in the control unit 321.

  The abnormality detection unit 321e detects an abnormality that has occurred in the power supply control system. That is, the abnormality detection unit 321e receives an abnormality occurrence signal transmitted by the microcomputer when an abnormality occurs in the microcomputer mounted on the electronic control device that controls the auxiliary machine 6, thereby allowing the power supply control system to Detect that an abnormality has occurred. The abnormality detection unit 321e functions as an abnormality detection unit.

<2-3. Processing>
FIG. 13 is a flowchart showing processing steps of the DDC driver 32 according to the second embodiment.

  First, the abnormality detection unit 321e determines whether an abnormality has occurred in the microcomputer mounted on the electronic control unit that controls the auxiliary machine 6 (step S21).

  If the abnormality detection unit 321e determines that no abnormality has occurred (No in step S21), the DDC driver 32 does not perform discharge control and continues to perform power supply control so that the auxiliary machine 6 and the like are normally driven ( Step S22).

  On the other hand, when the abnormality detection unit 321e determines that an abnormality has occurred (Yes in step S21), as described above, a series of processing from step S12 to step S16 is executed, and the charge of the capacitor 4 is transferred to the battery 5 and the ground GND. Discharged.

  As described above, the DDC 3 according to the second embodiment performs the discharge control of the capacitor 4 when an abnormality occurs in the power supply control system. Thereby, before the power supply control system is stopped in response to the occurrence of the abnormality, the charge of the capacitor 4 can be surely discharged, and the deterioration of the capacitor 4 can be prevented.

<3. Third Embodiment>
Next, a third embodiment will be described. The third embodiment includes a configuration similar to that of the first embodiment. Therefore, differences from the first embodiment will be mainly described below.

<3-1. Overview>
In the first embodiment, the charge discharge control of the capacitor 4 is performed when the ignition switch IGSW is turned off. In the third embodiment, discharge control is performed when the capacitor 4 is replaced. By reliably discharging the capacitor 4 before replacing the capacitor 4, it is possible to prevent electric shock of the operator and burning of the electronic components when the capacitor 4 is replaced and removed. That is, the safety of replacement and removal work of the capacitor 4 can be improved.

<3-2. Configuration>
FIG. 14 shows a configuration of the DDC driver 32 included in the DDC 3 according to the third embodiment. In the DDC driver 32 according to the first embodiment described above, the control unit 321 includes the IG detection unit 321a. On the other hand, the DDC driver 32 according to the third embodiment includes a replacement detection unit 321f in the control unit 321.

  The exchange detection unit 321f detects that the capacitor 4 is exchanged and removed. That is, the exchange detection unit 321f detects that the capacitor 4 is exchanged and removed by receiving an exchange signal input in advance to the control unit 321 when the operator exchanges and removes the capacitor 4. Before removing the capacitor 4, the operator turns on the ignition switch IGSW and inputs an exchange signal by rewriting the flash memory of the microcomputer of the control unit 321. The exchange detection unit 321f functions as an exchange detection unit.

<3-3. Processing>
FIG. 15 is a flowchart showing processing steps of the DDC driver 32 according to the third embodiment.

  First, the exchange detection unit 321f determines whether or not an exchange signal has been input by rewriting the flash memory of the microcomputer (step S31).

  If the exchange detection unit 321f determines that no exchange signal is input (No in step S31), the DDC driver 32 does not perform any control and the process ends.

  On the other hand, when the exchange detection unit 321f determines that the exchange signal has been input (Yes in step S31), as described above, a series of processing from step S12 to step S16 is executed, and the charge of the capacitor 4 is changed to the battery 5 and the ground GND. Is discharged.

  As described above, the DDC 3 according to the second embodiment performs the discharge control of the capacitor 4 when the capacitor 4 is replaced. As a result, it is possible to prevent the operator from electric shock and burnout of the electronic parts during the replacement and removal of the capacitor 4, and improve the safety of the replacement and removal work of the capacitor 4.

<4. Modification>
The present invention is not limited to the above embodiment. The present invention can be modified. Hereinafter, modifications of the present invention will be described. The embodiments described above and below can be combined as appropriate.

  In the said embodiment, the battery 5 which used lead for the electrode was shown as main power supplies of the electric equipment with which the vehicle 2 is equipped. However, the power source may not be the battery 5. Any secondary battery that can serve as a power source for the electrical equipment provided in the vehicle 2 may be used. For example, a silicon battery.

  Moreover, in the said embodiment, the capacitor 4 was shown as an auxiliary power supply of the electric equipment with which the vehicle 2 is equipped. However, the auxiliary power supply need not be the capacitor 4. Any secondary battery that can serve as an auxiliary power source for electrical equipment provided in the vehicle 2 may be used. For example, a lithium ion battery or a nickel-hydrogen rechargeable battery.

  Moreover, in the said embodiment, it demonstrated that the power supply control system 1 was mounted in a vehicle. However, the power supply control system 1 may be mounted on transportation equipment such as a motorcycle, a railway, an aircraft, and a ship. Furthermore, it may be mounted on an elevator such as an elevator or an escalator. In short, what is necessary is just to be connected to a power source and an electric load and to perform discharge control on the power source and energization control on the electric load.

  Further, the configuration described as hardware may be realized by software. On the other hand, the function described as software may be realized by hardware. Further, hardware or software may be realized by a combination of hardware and software.

1 Power Control System 2 Vehicle 3 Converter 4 Capacitor 5 Battery 6 Auxiliary Machine 7 Starter 8 Alternator 9 Main Relay

Claims (9)

A vehicle power supply control device for use in a vehicle,
Discharge means for performing first discharge control for discharging electric charge accumulated in a capacitor provided in the vehicle to a secondary battery that drives a device mounted on the vehicle, and second discharge control for discharging to a ground. When,
Determination means for determining whether the charge amount of the secondary battery has reached a predetermined threshold;
With
The vehicle power supply control device according to claim 1, wherein the discharge unit executes the second discharge control when a charge amount of the secondary battery reaches the predetermined threshold during the execution of the first discharge control. In the vehicle power supply control device according to claim 1,
The vehicle power supply control device according to claim 1, wherein the discharge unit performs the second discharge control while performing current restriction for restricting a current flowing through the capacitor. In the vehicle power supply control device according to claim 2,
The vehicle power supply control device according to claim 1, wherein the discharging means performs the current limitation by performing step-down control for stepping down a voltage applied by the capacitor. In the vehicle power supply control device according to claim 3,
A first switch element that opens and closes a circuit connecting the capacitor and the ground;
An inductor connected between the first switch element of the circuit and the ground;
Further comprising
The vehicle power supply control device according to claim 1, wherein the discharge means performs the step-down control by switching the first switch element. In the vehicle power supply control device according to any one of claims 1 to 4,
The discharging means has a primary side connected to the capacitor, the first switch element and the second switch element, and a secondary side connected to the secondary battery, the third switch element and the fourth switch element, A vehicular power supply control device comprising an H-bridge circuit in which the inductor is connected between a primary side and the secondary side. In the vehicle power supply control device according to any one of claims 1 to 5,
Ignition detecting means for detecting that an ignition switch provided in the vehicle is turned off;
Further comprising
The vehicle power supply control device according to claim 1, wherein the discharge means discharges the electric charge accumulated in the capacitor when the ignition switch is turned off. In the vehicle power supply control device according to any one of claims 1 to 5,
An abnormality detecting means for detecting an abnormality of the vehicle power supply control device;
Further comprising
The vehicle power supply control device, wherein the discharge means discharges the electric charge accumulated in the capacitor when the abnormality is detected. In the vehicle power supply control device according to any one of claims 1 to 5,
Replacement detection means for detecting replacement of the capacitor;
Further comprising
The vehicle power supply control device according to claim 1, wherein when the capacitor is replaced, the discharging means discharges the electric charge accumulated in the capacitor. A method of controlling a vehicle power source used in a vehicle,
(A) discharging the electric charge accumulated in the capacitor provided in the vehicle to a secondary battery that drives a device mounted on the vehicle;
(B) determining whether the amount of charge of the secondary battery has reached a predetermined threshold;
(C) discharging the charge accumulated in the capacitor to the ground when the charge amount of the secondary battery reaches the predetermined threshold during the step (a);
A control method for a vehicle power supply.

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